Here is a footnoted statement from Wikipedia:'A month before the end of the war, Polk was criticized in a United States House of Representatives amendment to a bill praising Major General Zachary Taylor for "a war unnecessarily and unconstitutionally begun by the President of the United States". This criticism, in which Congressman Abraham Lincoln played an important role with his Spot Resolutions, followed congressional scrutiny of the war's beginnings, including factual challenges to claims made by President Polk.' Footnotes: Congressional Globe, 30th Session (1848) pp.93-95
House Journal, 30th Session (1848) pp.183-184
B: The Mexican-American War has begun.